Forward osmosis with an organic osmolyte for cooling towers

Abstract

A system is described in which a cooling tower is operated with a solution of a non-volatile organic molecule osmolyte and water. Makeup water for the tower is provided by forward osmosis using the fluid as the draw solution for the extraction of water from feeds which require dewatering or from low value available water.

1 . A method for cooling hot process fluid, comprising:
 (a) conveying through a first side of a heat exchanger the hot process fluid, and conveying through a second side of the heat exchanger an organic osmolyte solution which absorbs heat from the hot fluid;   (b) conveying the organic osmolyte solution to a cooling tower;   (c) diluting the organic osmolyte solution with water produced by a forward osmosis element, to produce diluted osmolyte solution; and   (d) conveying diluted osmolyte solution through the second side of the heat exchanger.   
     
     
         2 . The method of  claim 1 , wherein the water produced in step (c) by the forward osmosis element is extracted from a membrane bioreactor; sea water; landfill leachate; oil drilling mud; gas drilling mud; produced water; flowback water; refinery wastewater; pulp manufacturing wastewater; paper manufacturing wastewater; pharmaceutical processing wastewater; water obtained from concentrating food substances; and water obtained from concentrating pharmaceuticals. 
     
     
         3 . The method of  claim 1 , wherein the organic osmolyte is liquid in its pure state at ambient temperatures. 
     
     
         4 . The method of  claim 1 , wherein the osmolyte is one or more selected from the group consisting of the following: trimethylamine N-oxide (TMAO), dimethylsulfoniopropionate, trimethylglycine, sarcosine, glycerophosphorylcholine, myo-inositol, taurine, betaines, amino acids, polyols, monosaccharides, disaccharides, polysaccharides, methylamines, methylsulfonium compounds, urea and glyceryl triacetate, polyvinyl alcohol, neoagarobiose, trehalose, and natural extracts. 
     
     
         5 . The method of  claim 4 , wherein
 the amino acid is selected from the group consisting of Histidine, Alanine, Isoleucine, Arginine, Leucine, Asparagine, Lysine, Aspartic acid, Methionine, Cysteine, Phenylalanine, Glutamic acid, Threonine, Glutamine, Tryptophan, Glycine, Valine, Ornithine, Proline, Selenocysteine, Serine, Taurine and Tyrosine;   the polyol is selected from the group consisting of ethylene glycol, propylene glycol, glycerol and polyethylene glycol;   the monosaccharide is selected from the group consisting of glucose and fructose;   the disaccharide is selected from the group consisting of sucrose and lactose;   the polysaccharide is selected from the group consisting of cellulose, polydextrose and amylose; and   the natural extract is selected from quillaia and lactic acid.   
     
     
         6 . The method of  claim 1 , further comprising subjecting the diluted osmolyte to electrodialysis to remove excess salts. 
     
     
         7 . A forward osmosis system for use with a heat exchanger and a cooling tower using an organic osmolyte solution as cooling tower water, the system comprising a forward osmosis membrane element for diluting a stream of organic osmolyte solution exiting the cooling tower. 
     
     
         8 . The system of  claim 7 , wherein the forward osmosis membrane element uses a feed solution for the forward osmosis membrane element selected from the group consisting of: membrane bioreactor water; sea water; landfill leachate; oil drilling mud; gas drilling mud; produced water; flowback water; refinery wastewater; pulp manufacturing wastewater; paper manufacturing wastewater; pharmaceutical processing wastewater; water obtained from concentrating food substances; and water obtained from concentrating pharmaceuticals. 
     
     
         9 . The system of  claim 7 , wherein the organic osmolyte is selected from the group consisting of: trimethylamine N-oxide (TMAO), dimethylsulfoniopropionate, trimethylglycine, sarcosine, glycerophosphorylcholine, myo-inositol, taurine, betaines, amino acids, polyols, monosaccharides, disaccharides, polysaccharides, methylamines, methylsulfonium compounds, urea and glyceryl triacetate, polyvinyl alcohol, neoagarobiose, trehalose, and natural extracts. 
     
     
         10 . The system of  claim 7 , wherein: the amino acid is selected from the group consisting of Histidine, Alanine, Isoleucine, Arginine, Leucine, Asparagine, Lysine, Aspartic acid, Methionine, Cysteine, Phenylalanine, Glutamic acid, Threonine, Glutamine, Tryptophan, Glycine, Valine, Ornithine, Proline, Selenocysteine, Serine, Taurine and Tyrosine;
 the polyol is selected from the group consisting of ethylene glycol, propylene glycol, glycerol and polyethylene glycol;   the monosaccharide is selected from the group consisting of glucose and fructose;   the disaccharide is selected from the group consisting of sucrose and lactose;   the polysaccharide is selected from the group consisting of cellulose, polydextrose and amylose; and   the natural extract is selected from quillaia and lactic acid.   
     
     
         11 . The system of  claim 7 , further comprising an electrodialysis unit for removing salts from diluted organic osmolyte solution exiting the forward osmosis membrane element. 
     
     
         12 . A cooling tower system comprising:
 (a) a heat exchange loop comprising:
 a heat exchanger having a first side and a second side, and 
 a first conduit for conveying hot process fluid through the first side of the heat exchanger; 
   (b) a cooling tower;   (c) a second conduit for conveying an organic osmolyte solution through the second side of the heat exchanger into the cooling tower;   (d) a forward osmosis membrane element for producing dilute organic osmolyte solution;   (e) a third conduit for conveying concentrated organic osmolyte solution exiting the bottom of the cooling tower to the forward osmosis membrane element; and   (f) a fourth conduit for conveying diluted organic osmolyte solution exiting the forward osmosis membrane element to the second side of the heat exchanger.   
     
     
         13 . The cooling tower system of  claim 12 , further comprising an electrodialysis unit for removing salts from diluted organic osmolyte solution exiting the forward osmosis membrane element.